My invention relates to dispensers of flowable material in general and more specifically to those meant for mounting on a fish tank for dispensing of dry fish food onto the surface of the water. Usually dispensers of this type are used with timing means to provide periodic automatic fish feeding.
For an automatic fish feeder to be a practical addition to any aquarium it must be able to dispense the proper quantity of a given fish food, dispense it at an appropriate time, be unobtrusive so as not to detract from the beauty of the aquarium, and be priced competitively with other aquarium accessories.
When feeding aquarium fish, a sufficient quantity of food must be instantaneously deposited on the water so the aggressive fish can't consume it all before the others feed. At the same time, care must be taken not to feed in excess because unconsumed food spoils the water.
Dispensers of prior art devices are coupled to a synchronous motor geared to produce an output drive of one or two revolutions a day to provide the periodic automatic fish feeding. The dispenser coupled to such a motor must include mechanical means to both adjust the amount of food dispensed and to dispense it instantaneously.
A prototype fish feeder of my design consists of a dispenser of my invention coupled to an electronically controlled rotatable drive shaft. A presettable electronic clock triggers the occurrence of feeding, and the amount dispensed is an electronic preset for the number of rotations of the dispenser which dispenses a constant quantity of food each rotation. Because the set number of rotations are executed fairly rapidly, the tasks of adjusting the quantity dispensed and of dispensing it instantaneously are addressed by the electronic control module.
The prototype fish feeder of my design provides settings for 1 to 10 rotations of the dispenser. This provides a range of quantity dispensed that is difficult to match by mechanical means given one rotation. Furthermore, when a number of rotations are required to dispense the desired quantity, a consistent dispensed quantity is achieve because the individual dispenses are averaged. A further advantage of this rotating dispenser is the mixing action which allows the aquarist to fill the dispenser with an assortment of fish foods for simultaneous dispensing.
An inherent problem of fish feeders incorporating a synchronous motor is that the port in the dispenser through which food is dispensed is either permanently facing the water, or it spends several hours of a 24 hour period in a downward position. The dispense port then provides a channel for the rising water vapor to enter the dispenser, and the dry fish food within may clot together in the presence of this extra moisture and jeopardize the dependability of the fish feeder.
The electronic control module allows the dispenser of my invention to remain stationary between occurences of dispensing, in a position with its dispense port protected from rising water vapor.
Because adjusting the quantity dispensed, dispensing it instantaneously, and keeping the fish food dry are all challenges met by an electronic control module as previously described. A fish food dispenser of my invention specializes in adapting to the various forms and sizes of fish food available to assure that an appropriately small quantity of food is dispensed each rotation.
By doing so, multiple rotations of the dispenser are required to dispense a sufficient quantity of food in the aquarium, and this dispensed quantity may be easily adjusted by increasing or decreasing the number of dispenser rotations.
Added benefits of the dispenser of my invention include no moving parts, and the absence of any small holes or crevices that may otherwise clog with large food particles.
Prior art dispensers were designed to perform well with granular food which exhibits a sand-like flow charateristic, but exhibit various degrees of ability to dispense fish food consisting of larger particles such as flakes, pellets, and stick foods which are now popular.